Proton Beam Re-Irradiation for Recurrent Head and Neck Cancer : Multi-Institutional Report on Feasibility and Early Outcomes
Menée à partir de données portant sur 92 patients atteints d'un cancer de la tête et du cou ayant récidivé après radiothérapie externe (durée médiane de suivi : 13,3 mois), cette étude multicentrique évalue l'efficacité, du point de vue des taux actuariels de survie sans métastase distante et de survie globale à un an, et la toxicité d'une seconde irradiation par protonthérapie
Purpose/Objectives : Re-irradiation (re-RT) is the only potentially curative treatment option for patients with locally recurrent head and neck cancer (HNC). Given the significant morbidity with head and neck re-irradiation, interest in proton beam radiotherapy (PBRT) has increased. Herein, we report the first multi-institutional clinical experience using curative intent PBRT for re-RT in recurrent HNC. Materials/Methods : A retrospective analysis of ongoing prospective data registries from 2-hybrid community practice and academic proton centers was conducted. Patients with recurrent HNC who had at least one prior course of definitive intent external beam RT were included. Acute and late toxicities were assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 and by the Radiation Therapy Oncology Group late radiation morbidity scoring system, respectively. The cumulative incidence of locoregional failure was calculated with death as a competing risk. The actuarial twelve-month freedom from distant metastasis (FFDM) and overall survival (OS) rates were calculated with the Kaplan-Meier method. Results : Ninety-two consecutive patients were treated with curative intent re-RT with PBRT between 2011 and 2014. Median follow-up among surviving patients was 13.3 months and among all patients was 10.4 months (interquartile range, 5.3-17.5 months). The median time between last RT and PBRT was 34.4 months. There were 76 patients with one prior RT course and 16 with two or more courses. Median PBRT dose was 60.6 Gy (RBE). Eighty-five percent of patients had prior HNC RT for an oropharynx primary and 39% had salvage surgery prior to re-RT. The cumulative incidence of locoregional failure at 12-months, with death as a competing risk, was 25.1%. Actuarial 12-month FFDM and OS were 84.0% and 65.2%, respectively. Acute grade ≥3 toxicities included mucositis (9.9%), dysphagia (9.1%), esophagitis (9.1%), and dermatitis (3.3%). There was one death during PBRT secondary to disease progression. Grade 3 or greater late skin and dysphagia toxicity were noted in 6 (8.7%) and 4 (7.1%) of patients, respectively. Two patients had grade 5 toxicity secondary to treatment-related bleeding. Conclusions : Proton beam re-irradiation of the head and neck can provide effective tumor control with acceptable acute and late toxicity profiles likely secondary to the decreased dose to the surrounding normal, albeit previously irradiated tissue, though longer follow up is needed to confirm these findings.